Mechanical pencil having a push button, step by step feed



Nov. 27, 1956 F. J. CRIBBS ETAL 2,771,858 MECHANICAL PENCIL HAVING A PUSH BUTTON, STEP BY STEP FEED Filed sept. s, 1955 INVENTORS. *FEANCIS J. ceaaes THOMAS ATTORNEYS nite 2,771,sss

MECHANICAL PENCIL HAVING A PUSH BUTTON, STEP BY STEP FEED This invention relates to mechanical pencils, and more particularly has reference to a pencil wherein the depression of a push button at the end of the pencil remote from the writing end thereof is effective to extend the lead for a predetermined part of its length.

Summarized brietly, the invention includes a barrel in which is axially shiftable a push rod terminating in a button projecting beyond one end of the barrel, the push rod being operably engaged by means of a pawl with a rack, and the barrel carrying a holding pawl which prevents retrograde movement of the rack. On each depression of the push button, the rack is advanced a predetermine-d number of steps and carried by the rack is a lead which is correspondingly advanced on each advancing movement of the rack. Associated with the rack is a means for rotating the same at the option of a user, through a sufiicient number of degrees to disengage the same from the pawls, and when the rack is so rotated, a spring means associated therewith returns it to its original position, so that a new lead can be inserted.

The main object of the present invention is to provide a generally improved mechanical pencil, which, by reason of the use of a means for effecting step by step advancement of the lead, will permit extension of a selected portion of the lead with far greater speed and ease than is true of the widely known type of mechanical pencil in general use today, wherein the advancement of the lead requires a twisting or rotatable movement of a portion of the barrel or other exposed part of the device, either through a number of revolutions or at least through a substantial part of a single revolution, before the lea will have been extended a sufficient distance.

The main objects of the invention may be stated to be the provision of a mechanical pencil that will be characterized by the simplicity and swift operation of the mechanism used for advancing the lead; that will insure the advancement of the lead for an exact, predetermined distance beyond the adjacent end of the barrel on each loccasion on which the lead is advanced; will be further characterized by the ease and swiftness with which the mechanism within the barrel may be adjusted to a position in which it is adapted to receive a new piece of lead; will be compact; and will be of relatively simple design permitting the manufacture of the pencil at a comparatively low cost, considering the advantageous features incorporated therein.

Other objects will appear from the following description, the claim appended thereto, and from the annexed drawing, in which like reference characters designate like parts throughout the several views, and wherein;

Figure l is a longitudinal sectional view through a pencil formed according to the present invention, the lead and the lead advancing mechanism being shown in their initial position, immediately following insertion of a new piece of lead;

Figure 2 is a view similar to Figure l in which the plunger or push rod has been depressed for the purpose of advancing the lead;

tates Patent 2,771,858 Patented Nov. 27, 1956 TQS Figure 3 is an enlarged transverse sectional view on line 3-3 of Figure l;

Figure 4 is an enlarged transverse sectional view on line 4 4 of Figure l; and

Figure 5 is an enlarged transverse sectional view on line 5 5 of Figure l.

The reference numeral 10 designates the barrel of the pencil, said barrel being formed as a cylinder of constant diameter for the greatest part of its length, the barrel at its outer end being integrally formed with a tapering portion merging into an inwardly turned circumferential lip 12 defining an axial opening 14 in the upper end of the barrel. The term upper end is here used, and will be used hereinafter, to designate the end of the barrel opposite that from which the lead extends, and does not necessarily mean that the end of the barrel having openings 14 would necessarily be positioned as the upper end in every instance when the pencil is in use.

Rigid with the inner surface of the barrel, at a location slightly above the midlength point thereof, is an inwardly directed flange 16 defining an axial opening 18 within the barrel. Spaced longitudinally of the barrel from iiange 16 is a transverse partition 20 integral or otherwise made rigid with the barrel, having (see Figure 4) a keyhole slot 22 comprising a center opening aligned with the opening 14, 18, said center opening communieating with a lateral, relatively narrow extension 24.

At the lower end of the barrel, there is formed an outwardly facing circumferential shallow recess 26 receiving the cylindrical inner end 28 of a tapering nose 3i) integrally formed at its outer, smaller end with a small diameter, cylindrical, axial extension 32.

Extending axially of and within the barrel is a plunger or push rod 34, the outer end of which projects through the opening 14 to provide a depressible button 35. Plunger 34 has an outwardly directed collar 36 integrally formed thereon adjacent the inner end of the plunger, the collar 36 being adapted to bear against the shoulder detined by the tiange 16 of the barrel in normal position of the plunger shown in Figure l. A coil spring 38 is held under compression between the collar 36 and the partition 2G, and is tensioned to normally engage the collar against the shoulder 16.

Formed in the plunger 34 is an elongated, axial bore 4o, said bore 4u being formed with a tiare open end 42 opening upon the inner end of the plunger, the other end of the bore being closed and terminating adjacent the outer extremity of the plunger. An elongated rack 44 of cylindrical cross section is slidable within the bore 49 and projects at one end through the open end of the bore. Rack 44 has, for the greatest part of its length, rack teeth 46, adapted to be engaged by a pawl 48 mounted upon the plunger 34 within a suitable opening formed in the side wall of the plunger adjacent the outer end of the bore. Pawl 48 is provided with a spring stressed to normally engage the pawl in abutting relation to a selected rack tooth 45.

The pawl 48 may be appropriately termed an advancing pawl, since it is used to shift the rack 44 downwardly responsive to depression of the button 35, the downward movement of the rack being adapted to advance a lead carried thereby.

Also provided in the interior mechanism of the pencil is a holding pawl 50, pivotally mounted within the reduced lateral extension 24 of opening 22 (Figure 4). A leaf spring 52, anchored at one end to the inner surface of the barrel side wall, has its other end bearing against the pawl 50, and is tensioned to normally engage the pawl 50 yagainst the rack, in abutting relation to a selected rack tooth. r

From the description so far provided, it will be seen that when the button 3S is depressed to shift the plunger 34 Vfrom the Figure l position thereof to the Figure 2 position, pawl 48 will, by reason of its engagement with a particular tooth 46, cause the downward movement of the plunger 34 to effect conjoint downward or advancing movement of the rack 44. As the rack if-i moves downwardly, the pawl 59 ratchets over the teeth i When the plunger has been fully depressed to its Figure 2 position, the pawl 50 will engage one of the teeth 46, and will hold the rack against retrograde movement from the position to which it has been advanced.

The user, on -releasing the button 35, frees the plunger 34 for return movement to its Figure l position, under the pressure exerted by spring 3S against collar 36. As previously noted, the rack 44 will remain, by reason of the engagement of the holding pawl with the rack teeth, in its advanced position.

In the lower portion of the barrel, there is provided a means for permitting return movement of the rack ftd, after said rack has been advanced to its maximum extent, resulting in the need for inserting a new piece of lead. A disc 54 is integrally formed upon the lower end portion of rack 44, and defines a hat, circular shoulder thereon the periphery of which is closely spaced from the inner surface of the barrel side wall as shown in Figv ure 5. Formed in the periphery of disc i4 are diametrically opposed, rectangular notches S6, and extending through said notches are correspondingly diametrically opposed connecting rods 58, bowed outwardly intermediate their ends into frictional engagement with the barrel, so as to be normally held against rotation within the barrel. The connecting rods can be of a springable material, to provide for the desired frictional contact between the rods and the barrel side wall.

At one end, rods 58 are fixedly secured to an inner end wall 60, having a large center opening 62 through which the vrack extends. At their other ends, the rods are flxedly secured to an end wall 64, integral with a depending, slightly tapering skirt 66 formed at its smaller, lower end with a more steeply tapered extension 63 bearing against land xedly secured to the inner surface of the nose 30.

The elements 58 through 68 together define a cage generally designated at 69 and xedly secured to the nose 30, for rotation with said nose. The cage receives the rack, and by extension of the rods 58 through the disclike collar 54 of the rack, is related to the rack in such a way that the rack is freely slidaole within the cage during the advancement of the rack hereinbefore described, but is at the same time connected to the cage for rotation therewith.

Formed in the lower end of the rack 44 is a small diameter, axial recess 70, receiving the inner end of a pencil lead 72, the outer end of which is guided through the cylindrical extension 32 and projects beyond said extension.

It will not be seen that whenever the button 35 is depressed, the lead 72 will be extended a distance corresponding to that which the plunger 34 was moved responsive to depression of the button end thereof. The lead, accordingly, is advanced each time a predetermined distance beyond the cylindrical extension 32, with the lead being extended without requirement of rota-ting any portion of the pencil relative -to any other portion, and being, instead, instantaneously advanced responsive to depression of the button.

The plunger, as previously mentioned, returns immediately to its normal, extended position,

As the lead wears down, successive depressions of the button result in successive advancement of the lead, until ultimately, the rack will have been advanced to its maximum extent, with its axially recessed end bearing against the end wall 64. The remaining portion of the lead is now pulled out of the pencil and discarded, and to insert a new lead, one merely grasps the nose 30 and rotates it through approximately 90 degrees relative to the barrel, in either direction. This rotates cage 69, rotating, in turn, rack 44 to an extent suicient to disengage rack 44 from holding pawl 50. A new lead is now inserted through the extension 32 and is engaged in the axial recess 70. The lead is pressed in an axial direction inwardly of the barrel, and causes a corresponding movement of the rack, until the rack movement is halted by engagement of collar 54 against the end wall 60.

The nose 30 is now turned 90 degrees once again, to dispose the rack teeth 46 for engagement by pawls 48, Si! and the pencil is again ready for use.

lt will be seen that as distinguished from the mechanical pencils in general use today, the advancement of the lead is accomplished by a push button action, rather than by continued rotation of a portion of the pencil. Further, ordinarily, to prepare the conventional pencil for receiving a new lead, reverse rotation of said portion of the pencil must be resorted to, through a substantial number of revolutions, until the inserted lead is fully retracted within the pencil. In the instant invention, the reloading of the pencil is accomplished merely by rotation of nose 30 through 90 degrees in either direction, and a simple pushing movement of the lead in an axial direction, followed by another degree rotatable movenient of the nose Si), again in either direction.

lt will be understood to facilitate manufacture of the pencil, the barrel can be constructed in sections, which can be threadedly or otherwise separably but ixedly connected to one another, to provide access to the interior thereof for insertion of the mechanisms illustrated and described herein. This is believed sufficiently within the skill of those working in the art so as not to require special illustration herein.

lt is believed apparent that the invention is not necessarily confined to the speciiic use or uses thereof described above, since it may be utilized for any purpose to which it may be suited. Nor is the invention to be necessarily limited to the speciiic construction illustrated and described, since such construction is only intended to be illustrative of the principles, it being considered that the invention comprehends any minor change in construction that may be permitted within the scope of the appended claim.

What is claimed is:

A mechanical pencil comprising a barrel; an axially recessed plunger extending axially of and within the barrel, said plunger being shiftable within the barrel in an axial direction and having one end projecting exteriorly of the barrel to provide a button depressible by a user; resilient, yielding means engaged between the barrel and plunger tensioned to normally bias the plunger in a direction to extend the same out of the barrel; a rack slidably mounted within the axial recess of the plunger, said plunger and rack being rotatable relative to each other; an advancing pawl carried by the plunger and engaging the rack to advance the same within the barrel responsive to depression of said button, rotatable movement of the plunger following advancement of the rack being adapted to free the plunger for return movement under the pressure of said means; a holding pawl carried by the barrel disposed to engage the rack in selected positions to which the same is advanced, to hold the rack against retrograde movement; a pencil lead carried by the rack and projecting exteriorly of the barrel, for extension of said lead out ot the barrel a distance corresponding to that which the rack is advanced; a nose rotatably mounted upon the barrel and having an opening through which said lead projects exteriorly of the barrel; and a cage connected to the nose for rotation therewith and extending longitudinally of. and within the barrel, said cage including rods extending between opposite ends of the cage and angularly spaced about the circumference of the cagegthe rack including a collar having notches formed therein within which notches the rods are engaged, thus to permit sliding movement of the rack within the cage, while interengaging the rack and cage for conjoint rotation, said rack when rotated responsive to rotation of the nose and cage disengaging from both of said pawls, whereby to free the rack for return movement to its initial position responsive to shifting of an inserted lead in an axial direc- 5 tion inwardly of the barrel.

References Cited in the tile of this patent UNITED STATES PATENTS 

